Systems and methods for an electrified heavy-duty vehicle

ABSTRACT

Methods and systems are provided for an electric heavy-duty vehicle. In one example, the vehicle includes a battery pack for supplying current to an electric motor of the vehicle, the battery pack arranged in a chassis of the vehicle and configured to form part of a floor of the vehicle. The vehicle also includes a motor coupled to front wheels of the vehicle, the front wheels having hub assemblies housing drive shaft adapters configured to permanently couple the hub assemblies to drive shafts of the front wheels, and a cradle configured to be mounted with electrical sub-systems of the vehicle.

FIELD

The present description relates generally to methods and systems for anelectrified heavy-duty vehicle.

BACKGROUND AND SUMMARY

An internal combustion engine heavy-duty vehicle may be configured withrear-wheel drive to enhance initial acceleration and increase traction.Increasing interest in reducing fossil fuel combustion has led toefforts to provide electric heavy-duty vehicles. In order toelectrically propel such vehicles, a large battery pack may be demanded.The battery pack may be positioned low in the vehicle, such as along achassis of the vehicle, and may have a large footprint, resulting inpackaging constraints along an underside of the vehicle. In someexamples, modifications to vehicle configuration are demanded toaccommodate incorporation of the battery pack. For example, in order tomaintain traction and torque at the vehicle wheels and also adjust forthe positioning of the battery pack, the vehicle may be adapted withfront-wheel drive (e.g., as the battery pack may not leave space for adrive shaft extending a length of the chassis), where providingelectrical regenerative capabilities at the vehicle front wheels may bedesirable. Reconfiguration of various vehicle electrical sub-systems,such as a hydraulic pump, an air compressor, an air conditioningcompressor, vehicle wiring harnesses, brake lines, etc. may also bedemanded due to installation of the battery pack. In addition,integration of the large battery pack into the vehicle in a manner whichallows the battery pack to be readily removed without compromising astructural integrity of the vehicle chassis may drive furthermodifications.

In one example, the issues described above may be addressed by anelectric vehicle having a battery pack for supplying current to anelectric motor of the vehicle, the battery pack arranged in a chassis ofthe vehicle and configured to form part of a floor of the vehicle, amotor arranged adjacent to the chassis and coupled to front wheels ofthe vehicle, the front wheels having hub assemblies housing drive shaftadapters, wherein the drive shaft adapters are configured to permanentlycouple the hub assemblies to drive shafts of the front wheels, and acradle positioned adjacent to the chassis along a frame of the vehicle,the cradle configured to be mounted with electrical sub-systems of thevehicle. In this way, the electric vehicle may be adapted withfront-wheel drive to accommodate incorporation of a large battery packand enable efficient packaging of sub-system power electronics.

For example, the hub assemblies of the front wheels may be four-wheeldrive hub assemblies modified to permanently couple to drive shafts ofthe front wheels by installing the drive shaft adapters in the hubassemblies. The drive shaft adapters may enable regenerative braking tobe implemented at the front wheels, thereby increasing a powerefficiency of the vehicle. In addition, an overall footprint of theelectrical sub-systems may be reduced by consolidating the sub-systemsonto the cradle. The cradle may be pre-assembled prior to installing inthe vehicle, thus reducing assembly time and simplifying coupling of thesub-systems to the vehicle.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a vehicle incorporating a battery packextending along a chassis of the vehicle from a bottom view.

FIG. 2 shows the vehicle incorporating the battery pack from a profileview.

FIG. 3 shows perspective view of an example of a battery pack which maybe included in a heavy-duty vehicle.

FIG. 4 shows the battery pack of FIG. 3 with an outer cover removed.

FIG. 5 shows a detailed view of an internal components of the batterypack.

FIG. 6 shows a cutaway view of an example of a drive shaft with a driveshaft adapter, which may be implemented in the heavy-duty vehicleincorporating the battery pack.

FIG. 7 shows a perspective view of the drive shaft adapter of FIG. 6.

FIG. 8 shows a profile view of the drive shaft adapter of FIG. 6.

FIG. 9 shows a cross-section of the drive shaft adapter of FIG. 6.

FIG. 10 shows a perspective view of a first example of a sub-systemcradle which may be included in the heavy-duty vehicle incorporating thebattery pack.

FIGS. 11A and 11B show perspective views of a second example of thesub-system cradle which may be included in the heavy-duty vehicleincorporating the battery pack.

FIGS. 12A and 12B show exploded views of the sub-system cradle of FIGS.11A and 11B.

FIGS. 13 and 14 show an exemplary configuration of the sub-system cradlein the heavy-duty vehicle incorporating the battery pack.

FIGS. 1-14 are shown approximately to scale.

DETAILED DESCRIPTION

The following description relates to systems and methods for anelectrified heavy-duty vehicle. In order to be electrically propelled,an electrical system of the vehicle may be adapted with a battery packarranged along a chassis of the vehicle, as shown in FIG. 1. In oneexample, the vehicle may be configured with a skateboard chassis wherethe battery is integrated into the skateboard chassis, as illustrated inFIG. 2. An example of the battery pack is shown in FIG. 3 from aperspective view and depicted in FIG. 4 with an outer housing removed. Amore detailed view of an internal structure of the battery pack is shownin FIG. 5. The electrified vehicle may be adapted with front-wheel driveto accommodate a positioning of the battery pack in the vehicle whileproviding a desired traction and acceleration at the vehicle wheels. Thevehicle may further be configured with regenerative braking to rechargethe battery pack. As such, the front wheels may include drive shaftadapters which allow regenerative braking to be conducted at the frontwheels. An example of a drive shaft adapter arranged in a wheel hub isillustrated in FIG. 6, in a cut-away view. The drive shaft adapter isshown in greater detail in FIGS. 7-9. To further accommodate placementof the battery pack in the vehicle, the vehicle may include a sub-systemcradle, as shown in the examples of FIGS. 10-12B, the sub-system cradleconfigured to consolidate mounting of electrical sub-systems of thevehicle onto a single structure, thereby simplifying assembly anddecreasing an overall footprint of the sub-systems. An exemplaryconfiguration of the sub-system cradle within the vehicle is furtherdepicted in FIGS. 13 and 14.

FIGS. 1-14 show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example. As yet another example, shapes of theelements depicted within the figures may be referred to as having thoseshapes (e.g., such as being circular, straight, planar, curved, rounded,chamfered, angled, or the like). Further, elements shown intersectingone another may be referred to as intersecting elements or intersectingone another, in at least one example. Further still, an element shownwithin another element or shown outside of another element may bereferred as such, in one example.

Turning now to FIG. 1, a heavy-duty vehicle 100 may have an electricalsystem configured with a battery pack 102 as a prime mover providingelectrical energy for propulsion. A set of reference axes 101 areprovided for comparison between views shown, indicating a y-axis, anx-axis, and a z-axis. In one example, the y-axis may be parallel with adirection of gravity and a vertical direction, the x-axis parallel witha horizontal direction, and the z-axis parallel with transversedirection and a longitudinal axis of the vehicle 100, e.g., parallelwith a length of the vehicle 100. The heavy-duty vehicle 100 may be avariety of vehicle types, including light commercial vehicles, buses ofdifferent sizes, medium- and heavy-duty trucks, vocational vehicles,etc. The battery pack 102 may be an energy storage device configured todeliver electrical power to various components of the electrical systemof the vehicle 100 including supplying current to motors coupled tofront wheels 104 and/or rear wheels 106 of the vehicle 100. The batterypack 102 may extend along a chassis 108 of the vehicle 100, between thefront wheels 104 and the rear wheels 106, along a portion of a length110 of the vehicle 100. A width 112 of the battery pack 102 may besimilar to a distance between innermost wheels of the rear wheels 106.

In one example, the chassis 108 of the vehicle 100 may be a skateboardchassis 108 in which the battery pack 102 is integrated, e.g., forming acontinuous unit with the skateboard chassis 108. The skateboard chassis108 may extend along a greater portion of the length 110 of the vehicle100 than the battery pack 102, from a point behind the front wheels 104to a rear end 116 of the vehicle. However, in other examples, theskateboard chassis 108 may vary in length, e.g., the skateboard chassis108 may be shorter than depicted in FIG. 1. In one example, as shown ina profile view 200 of the vehicle 100 in FIG. 2, the skateboard chassis108 may be a platform forming a floor of the vehicle 100. The skateboardchassis 108 may be formed of a solid, durable, strong material, such asaluminum, steel, fiber-reinforced materials, and/or other compositematerials, able to withstand and support large loads (e.g., a maximumload for which the vehicle 100 is designed to carry under predetermineduse cases or conditions).

The battery pack 102 may be embedded in the skateboard chassis 108,e.g., enclosed in a recess in the skateboard chassis 108, to form asingle integrated structure, and may therefore also be incorporated intothe floor of the vehicle 100. A bottom face 202 of the battery pack 102may form a portion of a bottom surface 204 of the skateboard chassis108. The battery pack 102 may therefore be biased within the skateboardchassis 108 at a lower region, with respect to the y-axis, of theskateboard chassis 108. However, in other examples, the battery pack 102may instead be biased at an upper region of the skateboard chassis 108with an upper face 206 of the battery pack 102 forming a portion of anupper surface 208 of the skateboard chassis 108. In yet other examples,the battery pack 102 may extend along a majority of a height 210 of theskateboard chassis 108.

The skateboard chassis 108 may provide various benefits with respect toefficient assembly and packaging of the vehicle 100. For example, theskateboard chassis 108 may be readily scalable, allowing different typesof vehicle bodies to be attached. Depending on a height of a payload ofthe vehicle 100, a low vertical (e.g., with respect to the y-axis)positioning of the battery pack 102 in the vehicle 100 may provide evenand balanced weight distribution without adversely affecting, or evenpositively contributing to, a balance of the vehicle 100. Furthermore,locating the battery pack 102 in the vehicle floor may increase cabinspace while enclosing the battery pack 102 in a durable, rigid structurethat supports and shields the battery pack 102 from contact with debris,moving vehicle components, etc.

Returning to FIG. 1, a positioning of the battery pack 102 in thevehicle 100 may result in locating electrical components, such aselectric motors, in a region between a front end 114 of the vehicle 100and a front edge 109 of the skateboard chassis 108. Thus, packagingspace is available between the front wheels 104, allowing implementationof a powertrain and a drive train at the front wheels 104 but not at therear wheels 106 when the vehicle 100 is adapted with the skateboardchassis 108.

In addition, the battery pack 102 itself may be a strong, rigidstructure and incorporating the battery pack 102 into the skateboardchassis 108 may further increase an overall stiffness, torsionalresistance, and bending resistance of the skateboard chassis 108. Bypositioning the battery pack 102 at the bottom region of the skateboardchassis 108, the battery pack may be easily accessible for maintenanceand/or replacement. As such, the battery pack 102 may be removablycoupled to the skateboard chassis 108 and configured as a frameintegrated independent sub-structure in the skateboard chassis 108. Inother words, the battery pack 102 has a stand-alone structure that isembedded into the skateboard chassis 108 but readily accessible and maybe removed when desired.

A perspective view 300 of the battery pack 102 is depicted in FIG. 3.The battery pack has a top cover (not shown at FIG. 3) and a bottomcover 302, where the bottom cover 302 may form the bottom face 202 ofthe battery pack 102 and be included in the bottom surface 204 of theskateboard chassis 108, as shown in FIG. 2. Accordingly, the bottomcover 302 may be formed of a rigid, durable material, such as steel,aluminum, a composite, etc. The top cover may be disposed opposite tothe bottom cover 302 along the y-axis. The top cover may be formed of aless rigid material than the bottom cover, such as molded plastic oranother polymer, the top cover not being exposed to an exterior of thevehicle 100. In other examples, the top cover may be formed of a samematerial as the bottom cover 302.

Reinforcing rails 304 may extend along a length 306 of the battery pack102 with braces 308 extending between each of the rails 304 and sideedges 310 of the bottom cover 302, at an angle relative to thereinforcing rails 304. The bottom cover 302 may further includeapertures 312 for receiving fasteners to secure the bottom cover 302 tothe skateboard chassis, e.g., the skateboard chassis 108 of FIGS. 1 and2. It will be appreciated that the bottom cover 302 illustrated in FIG.3 is a non-limiting example. Other examples may include variations inmechanisms and structures for coupling the bottom cover 302 to theskateboard chassis, as well as modifications to a geometry and relativedimensions of the bottom cover 302, without departing from the scope ofthe present disclosure.

The bottom cover 302 may provide a barrier between an internal structureof the battery pack 102 and external objects. The internal structure ofthe battery pack 102 may include a plurality of modules 402, as shown ina bottom view 400 of the battery pack 102 with the top cover removed andin a detailed view in FIG. 5 of dashed area 500. The plurality ofmodules 402 may be arranged in rows along the z-axis, spaced apart fromadjacent rows. Each module of the plurality of modules 402 includesmultiple cells 404 connected in series or parallel within the module402. The plurality of modules 402 may be connected in parallel andcoupled to electrical terminals 406 of the battery pack.

The battery pack 102 may include other internal components, such aselectrical interconnects, at least one contactor 408, at least onepre-charge resistor 410, solid-state relays (SSRs) 412, and at least onecurrent sensor 414, in addition to at least one temperature sensor, atleast one voltage sensor, at least one current sensor, a batterymanagement system, contactors, pre-charge resistors, high- andlow-voltage fuses, a resistive heating system, busbars, a coolingsystem, a connector and a 12V bus for supplying power to the variouselectronics, etc. The battery pack 102 may be configured with aslave-master battery management system with a manual service disconnect(MSD) (e.g., at the electrical terminals 406), integrated heat pads, andpre-charge capability. The cells 404 may have various capacities andchemistries, and may be configured in any one of a number ofseries-parallel module configurations.

As described above, by adapting the vehicle with the skateboard chassisand integrated battery pack, additional components of the vehicle'selectrical system, such as electric motors, may be positioned around theskateboard chassis, along a similar horizontal plane as the skateboardchassis. For example, an electric motor and a drive train may bearranged in front of the skateboard chassis, e.g., between the front end114 of the vehicle 100 and a front edge 109 of the skateboard chassis108 of FIG. 1, and between the front wheels 104. As such, the vehiclemay be configured with front-wheel drive, as shown in FIG. 1. Thevehicle 100 includes a motor 118 arranged proximate to the front end 114of the vehicle 100, between the front wheels 104, the motor 118configured to receive electrical power from the battery pack 102. In oneexample, the motor 118 may be a motor/generator, able to convertmechanical energy to electrical energy to recharge the battery pack 102.The motor 118 may be coupled to a drive train 120 which, in turn, iscoupled to drive shafts 122 of the front wheels 104. The drive train 120may include components such as a transmission and a differential. Atorque converter may be located between the motor 118 and thetransmission if the transmission is automatic, or a clutch may bearranged between the motor 118 and the transmission if the transmissionis manual or single-gear direct drive. Thus, electrical power drawn fromthe battery pack 102 by the motor 118 may be converted to torque todrive rotation of the front wheels 104 via the drive train 120. The rearwheels 106 may be trailer wheels rotated together on a single axle 152.

Implementing regenerative braking in the vehicle 100 may increase anefficiency and appeal of the vehicle 100 by allowing energy that mayotherwise be lost as waste heat to be at least partially recuperated.The recovered energy may be used to replenish battery charge with themotor 118 operating as a generator in such instances. However,conventional front wheel hub assemblies 124 compatible with motorizedfront wheels 104, such as front wheel hub assemblies used in heavy-dutyvehicles configured with four-wheel drive, may not be suitable forregenerative braking due to an automatic locking mechanism of theconventional front wheel hub assemblies. The use of front wheel hubassemblies with automatic locking mechanisms may disrupt regenerativebraking. For example, the automatic locking mechanism of a given frontwheel hub assembly may correspond to a ratchet mechanism. Specifically,the automatic locking mechanism may allow a corresponding front wheel104 to rotate freely about its drive shaft 122 when no torque isapplied, impeding regenerative braking by allowing free rotation of thefront wheel 104 absent applied acceleration torque (which in turn maynot brake the vehicle 100). Instead, regenerative braking is typicallymade possible via a rigid connection between the drive shafts and thewheels, such that when deceleration (braking) torque is applied, thewheels will not rotate freely and kinetic energy of the vehicle 100 maybe converted back to electrical energy. As an alternative, customizedfront wheel hub assemblies adapted for regenerative braking may bemanufactured. However, such customized front wheel hub assemblies may beundesirable due to a high cost of production.

One approach to address the issue described above includes replacing theautomatic locking mechanism of the conventional front wheel hubassemblies 124 with a drive shaft adapter 126, as indicated in FIG. 1,that enables regenerative braking to occur at the vehicle front wheels104. As such, the conventional front wheel hub assemblies may be used,e.g., as used for four-wheel drive applications, circumventingadditional costs arising from development of customized components, andadapted to assist in converting kinetic energy of the vehicle intoenergy stored at the battery pack 102. The drive shaft adapter 126 maybe directly coupled to each of the front wheel hub assemblies 124, incontact with the drive shafts 122 of the front wheels 104. An example ofone of the drive shaft adapters 126 is illustrated in FIG. 6, enclosedwithin one of the front wheel hub assemblies 124, from a cut-away view600.

The front wheel hub assembly 124 may extend through a central region ofone of the front wheels 104 such that at least a portion of the frontwheel hub assembly 124 is circumferentially surrounded by the frontwheel 104. The front wheel hub assembly 124 may be formed of a durable,rigid material, such as steel or aluminum and may include a wheel cover602, a wheel bearing 604, amongst other components. The front wheel hubassembly 124 may have a central opening 606 in which the wheel bearing604 is located. The wheel bearing 604 may similarly have a centralopening 608 through which the drive shaft adapter 126 is inserted.

The drive shaft adapter 126 may be circumferentially surrounded by thewheel bearing 604 and in direct contact with the wheel bearing 604. Thedrive shaft adapter 126 may extend along the x-axis, centered about acentral axis 610 of the front wheel hub assembly 124. A length 612, asdefined along the x-axis, of the drive shaft adapter 126 may be similarto a width, also defined along the x-axis, of the front wheel hubassembly 124. The drive shaft adapter 126 may be a hollow, tubularstructure with an inner passage 614 configured to receive a drive shaft,such as one of the drive shafts 122 of FIG. 1. The drive shaft adapter126 may couple with the drive shaft and the wheel bearing 604 so thatrotation of the drive shaft compels rotation of the drive shaft adapterand the wheel bearing 604 in unison with the drive shaft. The rotationof the wheel bearing 604 thereby drives rotation of remaining componentsof the front wheel hub assembly 124 and the front wheel 104, also inunison with the drive shaft.

The drive shaft adapter 126 is shown without the front wheel hubassembly 124 in FIGS. 7-9 from a perspective view 700, a profile view800, and a cut-away view 900, respectively. The drive shaft adapter 126may have a first portion 702 continuous with a second portion 704. Thefirst portion 702 may form a greater portion of the length 612 of thedrive shaft adapter 126 than the second portion 704. An outer diameterof the first portion 702 of the drive shaft adapter 126 may vary with alength of the first portion 702. For example, the first portion 702 mayinclude a first section 802 adjacent to and contiguous with the secondportion 704 of the drive shaft adapter 126, the first section 802 havinga uniform outer diameter 801, as shown in FIG. 8. The first portion 702may also have a second section 804 with a tapering outer diameter, e.g.,the outer diameter of the second section 804 decreases from the firstsection 802 to a third section 806 of the first portion 702 of the driveshaft adapter 126. The first portion 702 may further include the thirdsection 806 having a uniform outer diameter 803 that is narrower thanthe first section 802. While the outer diameter of the first portion 702of the drive shaft adapter 126 is not uniform, an overall change in theouter diameter is less than an overall change in an outer diameter ofthe second portion 704 of the drive shaft adapter 126, as describedfurther below.

An inner diameter 902, as shown in FIG. 9, of the first portion 702 (andof the inner passage 614 of the drive shaft adapter 126) may be uniformalong most of the length of the first portion 702 except for a flaredend 904 of the first portion 702, enclosed within the third section 806of the first portion 702, where the inner diameter 902 increases. Theinner diameter 902 of the first portion 702 may be similar to an outerdiameter of a drive shaft, adapted to fit tightly around an end of thedrive shaft so that the drive shaft and the drive shaft adapter 126rotate in unison, e.g., the drive shaft does not rotate relative to thedrive shaft adapter 126. The drive shaft adapter 126 may be coupled tothe drive shaft via a press fit connection, by welding, via a fasteningmechanism, and/or by a male-female mating configuration. In one example,the coupling of the drive shaft adapter 126 to the drive shaft may bepermanent, e.g., the drive shaft adapter 126 and the end of the driveshaft may not be detached from one another once coupled.

For example, the drive shaft adapter 126 may include a plurality of malesplines 708 on an outer surface 710 of the first portion 702. As shown,the plurality of male splines 708 may be substantially evenly spacedaround a circumference of the first portion 702, and may extend along atleast a portion of the outer surface 710 of the first portion 702 alongthe x-axis. A plurality of female splines (not shown at FIGS. 6-9) maybe correspondingly disposed on an inner surface of the wheel bearing604. The drive shaft adapter 126 may be press fit into the centralopening 608 of the wheel bearing 604 such that the plurality of malesplines 708 may respectively mate with the plurality of female splines.The inner passage 614 of the drive shaft adapter 126 may be loose fit toa spline of the drive shaft 122 (not shown at FIGS. 6-9) to form aconstant-velocity (CV) joint. The drive shaft adapter 126 may be fixedto the drive shaft 122 via a nut (not shown at FIGS. 6-9) fastened onthreads of an end of the drive shaft 122, the nut torqued to an innersurface 814 of the first section 802. A flange (e.g., third section 812,as described below) of the second portion 704 may be directly coupledand fastened to the wheel bearing 604 via a plurality of fasteners, suchas bolts, respectively fit into a plurality of fastener holes 706.Thesecond portion 704 of the drive shaft adapter 126 includes a firstsection 808 with a uniform outer diameter 805, as shown in FIG. 8, wherethe first section 808 is contiguous with the first section 802 of thefirst portion 702 of the drive shaft adapter 126. A second section 810of the second portion 704, the second section 810 having a taperingouter diameter that increases from the first section 808 to the thirdsection 812 of the second portion 704, is contiguous with the firstsection 808. The third section 812 of the second portion 704 of thedrive shaft adapter 126 is contiguous with the second section 810 andmay be a flange 812 with an outer diameter 807 forming a widest section,with respect to the y-axis, of the drive shaft adapter 126.

As illustrated in FIG. 9, an inner diameter 906 of the first section 808and a part of the second section 810 of the second portion 704 of thedrive shaft adapter 126 may be uniform along a length, as defined alongthe x-axis, of the second portion 704. Within the second section 810 andthe flange 812 of the second portion 704, the inner diameter of thesecond portion increases along a direction from the second section 810to the flange 812. The inner passage 614 of the drive shaft adapter 126at the second portion 704 of the drive shaft adapter 126 may beconfigured to receive each of a CV joint nut and a hubcap. As shown inFIG. 6, the flange 812 of the drive shaft adapter 126 may be shaped tointerface with both the wheel bearing 604 and the wheel cover 602 of thefront wheel hub assembly 124. The flange 812 may include the pluralityof fastener holes 706, as shown in FIGS. 7 and 9, to enable the driveshaft adapter 126 to be secured to the front wheel hub assembly 124 withfasteners, such as bolts. As such, the drive shaft adapter 126 may beconnected to the wheel bearing 604 via a combination of the fastenersand a press-fit connection, resulting in the drive shaft, the driveshaft adapter 126, and the front wheel hub assembly 124 rotating inunison around the central axis 610 when compelled to turn by a motor. Inother words, the drive shaft adapter 126 does not rotate relative to thedrive shaft or the front wheel hub assembly 124.

Implementing front-wheel drive in the heavy-duty vehicle whilemaintaining use of the automatic locking hubs may impose undesirablepower draw from a battery of the vehicle. Furthermore, the automaticlocking hubs may not be compatible with regenerative braking, thusinhibiting recovery of energy generated during vehicle speed reduction.By replacing the automatic locking hubs with the drive shaft adaptershown in FIGS. 6-9, the front wheel hub assemblies may be fixedlycoupled (e.g., the drive shaft adapter does not disengage from the frontdrive shaft) to the front drive shafts. Regenerative braking is therebyenabled at the vehicle front wheels. By replacing the automatic lockinghubs with the drive shaft adapter without demanding furthermodifications to the front wheel hub assemblies (e.g., modifications tothe wheel cover, the wheel bearing, and other components of the frontwheel hub assemblies not directly interfacing with the drive shaft),increases in a cost of the front wheel hub assemblies may becircumvented while providing efficient energy recovery.

As described above, implementation of a drive shaft adapter mayaccommodate a front-wheel drive configuration of an electrifiedheavy-duty vehicle adapted with a skateboard chassis with an integratedbattery pack. Packaging constraints imposed by the skateboard chassismay also demand rearrangement of power electronics of various vehicleelectrical sub-systems such as a hydraulic pump, an air pump, an airconditioning (A/C) compressor, a water pump, controllers, junctionboxes, fuses, a battery charger, inverters, etc., due to a verticallylow positioning of the skateboard chassis. The sub-systems are includedin an electrical system of the vehicle, drawing power from the batterypack. For example, as illustrated in FIG. 1, incorporation of thebattery pack 102 into the skateboard chassis 108 may demand positioningsub-systems power electronics in a region between the front edge 109 ofthe skateboard chassis 108 and the front end 114 of the vehicle 100where various other vehicle components already occupy at least a portionof the available packaging space. Positioning the power electronics ofeach of the sub-systems wherever each sub-system may be accommodated mayresult in use of long connectors, wires, and electrical cables which maybe directly coupled to a frame of the vehicle 100 to maintain theconnectors, wires, and cables off the ground. The connectors, wires, andcables may become easily tangled, degraded, and/or disconnected or comeinto contact with moving components of the vehicle 100. In addition, ascattered arrangement of the sub-systems may complicate access tocomponents of the sub-systems when maintenance and repair is demanded.

Furthermore, during assembly, individual coupling of the sub-systems tothe vehicle frame may be time consuming and include complex routing andtethering of connectors, wires, and cables. Sub-system components, suchas pumps, may demand installation of rubber mounts to dampentransmission of vibrations to the vehicle chassis, which increases anumber of parts to be attached to the vehicle and further adds toassembly time. In addition, individual coupling of the sub-systems mayresult in the sub-systems having an undesirably large footprint.

An overall footprint of the sub-systems power electronics may be reducedby mounting the power electronics on a single cradle. The cradle may bea supporting structure onto which the power electronics may be attached,thus consolidating the power electronics into a single unit. The powerelectronics may be assembled in the cradle prior to coupling to thevehicle. Electrical cables, vibrating components such as pumps, etc.,may be secured to the cradle rather than individually attached to thevehicle frame and the cradle, supporting sub-systems relying on powerfrom the battery pack, may be mounted to the vehicle frame in a positionthat allows convenient electrical coupling of the sub-systems to thebattery pack. In some examples, the power electronics may be attached tothe cradle without rubber supports. Instead, the cradle may be mountedto the vehicle chassis on rubber supports to reduce transmission ofvibrations to the vehicle from the sub-systems power electronics as asingle unit, thereby decreasing an amount of rubber supports forsuppressing propagation of vibrations.

As described above, a cradle may provide consolidation of powerelectronics for various electrical sub-systems of a vehicle, thusdecreasing an overall footprint of the sub-systems. The cradle may bepositioned in an accessible location along the vehicle frame, around theskateboard chassis and proximate to the battery pack 102 to enableelectrical coupling of the sub-systems to the battery pack 102 withoutuse of undesirably long cables. For example, as shown in FIG. 1, acradle 150 may be positioned along an underside of the vehicle 100,between the front end 114 and the skateboard chassis 108, along adriver's side of the vehicle 100. However, other examples may includethe cradle 150 arranged in other locations along the vehicle frame,similarly between the front end 114 and the skateboard chassis 108 (suchas on a passenger's side of the vehicle 100 or taking the place of aninternal combustion engine, e.g., in front of the vehicle cabin).Accordingly, the cradle 150 may be placed for ease of access formaintenance thereof.

The power electronics mounted on the cradle 150 may include varioussub-system controllers. The controllers may be communicatively coupledto a vehicle control unit 130, such as powertrain control module. Thecontrol unit 130 is a computing device, such as a microcomputer thatincludes a processor unit, a non-transitory computer-readable storagemedium device, input/output ports, memory, and a data bus.Computer-readable storage medium included in the control unit 130 isprogrammable with computer readable data representing instructionsexecutable by the processor for performing various control routines andmethods. Operation of the various sub-systems supported on the cradle150 may be controlled by the control unit 130, based on various sensorsand actuators (not shown) included in the vehicle 100.

A first example of a cradle 1000 for supporting power electronics ofvehicle sub-systems is shown in perspective view 1025 of FIG. 10. Thecradle 1000 includes a frame 1002 formed of a rigid, durable material,such as aluminum, steel (e.g., A36 steel), casted metal, etc. The frame1002 has a first compartment 1004 stacked over a second compartment1006, along the y-axis, with a floor 1008 extending along the x-z planetherebetween and dividing the first compartment 1004 from the secondcompartment 1006. Various sub-system components may be directly attachedto the frame 1002 of the cradle 1000 and/or within one or more of thefirst compartment 1004 and the second compartment 1006. For example, thesub-system components may be enclosed within each of the firstcompartment 1004 and the second compartment 1006 and also coupled toexternal surfaces of the frame 1002. The sub-system components mayinclude one or more of electrohydraulic brake and electrohydraulic powersteering pumps 1010, a heating, ventilation, and air-conditioning (HVAC)or air-conditioning (A/C) compressor 1012, one or more controllers 1014,one or more low-voltage fuse (e.g., 12V) boxes 1016, and one or morehigh-voltage coolant pumps 1018, in addition to other high-voltage powerelectronics including one or more of accessory inverters, high-voltagebattery chargers, high-voltage motor inverters, high-voltage DCDC units,etc. It will be appreciated that at least some sub-system components,such as the low-voltage fuse boxes 1016, may be positioned for ease ofaccess for maintenance.

Electrical cables, wires, as well as connectors such as pump hoses,tubing, etc., of the sub-system components may be directly coupled tothe cradle 1000 before the cradle 1000 is attached to a vehicle. Forexample, the sub-system components may be mounted onto the cradle at amanufacturing facility. The assembled cradle 1000 may then be secured toa frame of the vehicle via fastening devices such as bolts or by othermechanical fastening methods. In some examples, the cradle 1000 may beremovably coupled to the vehicle frame to allow detachment of the cradle1000 when maintenance and/or inspection of the sub-system components isdesired. Furthermore, rubber supports may be positioned between thecradle 1000 and the vehicle frame to absorb vibrations generated duringoperation of the sub-system components, such as the pumps 1010 and thecompressor 1012.

A second example of a cradle 1100 for supporting power electronics ofvehicle sub-systems is shown in perspective view 1125, perspective view1175, exploded view 1225, and exploded view 1275 of FIGS. 11A-12B,respectively. It will be appreciated that features of the second exampleof FIGS. 11A-12B may be embodiments of similarly labeled features of thefirst example of FIG. 10. For example, the frame 1102 may be anembodiment of the frame 1002.

The cradle 1100 includes a frame 1102 formed of a rigid, durablematerial, such as aluminum, steel (e.g., A36 steel), casted metal, etc.Though, the frame 1102 may be opaque in practice, the frame 1102 isdepicted as transparent in FIGS. 11A-12B so as not to obscure thevarious components included therein. The frame 1102 has a firstcompartment 1104 stacked over a second compartment 1106, along they-axis, with a floor 1108 extending along the x-z plane therebetween anddividing the first compartment 1104 from the second compartment 1106. Acavity 1103 may further be stacked over the first comportment 1104,along the y-axis. Various sub-system components may be directly attachedto the frame 1102 of the cradle 1100 and/or within one or more of thecavity 1103, the first compartment 1104, and the second compartment1106. For example, the sub-system components may be enclosed within eachof the cavity 1103, the first compartment 1104, and the secondcompartment 1106 and also coupled to external surfaces of the frame1102. The sub-system components may include one or more ofelectrohydraulic brake and electrohydraulic power steering pumps 1110 (asingle electrohydraulic power steering pump 1110 coupled to an inverter1132 therefor being depicted in the second example of FIGS. 11A-12B), anHVAC or A/C compressor 1112, one or more controllers 1114, one or morelow-voltage (e.g., 12V) fuse boxes 1116, a multiplex power distributionmodule (MPDM) 1120, a junction box 1122, one or more low-voltage (e.g.,12V) contactors 1126, a cabin heater unit 1130, and an electric powertakeoff (ePTO) system 1136 (not shown in FIGS. 11A and 11B so as not toobscure other components of the second compartment 1106) in addition toother high-voltage power electronics including one or more of accessoryinverters (e.g., inverter 1130), high-voltage battery chargers 1128,high-voltage motor inverters 1124, high-voltage DCDC units 1134,high-voltage coolant pumps, etc. It will be appreciated that at leastsome sub-system components, such as the low-voltage fuse boxes 1116, maybe positioned for ease of access for maintenance.

Electrical cables, wires, as well as connectors such as pump hoses,tubing, etc., of the sub-system components may be directly coupled tothe cradle 1100 before the cradle 1100 is attached to a vehicle. Forexample, the sub-system components may be mounted onto the cradle at amanufacturing facility. The assembled cradle 1100 may then be secured toa frame of the vehicle via fastening devices such as bolts or by othermechanical fastening methods. In some examples, the cradle 1100 may beremovably coupled to the vehicle frame to allow detachment of the cradle1100 when maintenance and/or inspection of the sub-system components isdesired. Furthermore, rubber supports may be positioned between thecradle 1100 and the vehicle frame to absorb vibrations generated duringoperation of the sub-system components, such as the pumps 1110 and thecompressor 1112.

The cradle of the present disclosure may be positioned in variouslocations of the vehicle relative to the chassis having the batterypack. For example, the cradle may be positioned in front of the chassisat the driver's side, the passenger's side, or therebetween (e.g.,taking the place of an internal combustion engine). In other examples,and as depicted in perspective view 1300 and cross section 1400 of FIGS.13 and 14, respectively, the cradle, such as the cradle 150, may bepositioned above an axle along the y-axis, such as the rear axle 152,between an innermost pair of wheels along the x-axis, such as betweenthe innermost pair of the rear wheels 106. Specifically, the cradle 150may account for the skateboard chassis 108 by being positioned adjacentto and at least partially within the skateboard chassis 108, e.g., abovean upper surface (e.g., 208) of the skateboard chassis 108 along they-axis, supported between and affixed to rails 1302 of the skateboardchassis 108 (as shown in FIGS. 13 and 14). It will be appreciated thateach component of the vehicle is not depicted in FIGS. 13 and 14 so asnot to obscure positioning of the cradle 150.

In this way, a heavy-duty vehicle may be electrified, powered by abattery pack integrated into a chassis of the vehicle where the chassisforms a floor of the vehicle. The integrated battery pack may beembedded into the chassis, reinforcing a structural integrity of thechassis, and configured to be removable to allow the battery pack to bereadily inspected and/or removed. The vehicle may be adapted withfront-wheel drive to accommodate a low vertical positioning of thechassis and battery pack. Front-wheel drive in the vehicle may beimplemented at low cost by utilizing conventional wheel hub assembliesand coupling the wheel hub assemblies to front drive shafts of thevehicle via drive shaft adapters. The drive shaft adapters may replaceautomatic locking hubs, thereby permanently coupling to the front driveshafts and enabling regenerative braking to be implemented at thevehicle front wheels. Constraints on packaging space for powerelectronics of vehicle sub-systems imposed by the vehicle chassis andbattery pack may be accommodated by mounting the power electronics ontoa single cradle, thereby providing a compact arrangement of thesub-systems at a single location. Mounting the power electronics of thesub-systems onto the cradle may also allow the sub-systems to be locatedclose to the battery pack from which the sub-systems may draw electricalpower. The cradle may be pre-assembled, reducing an amount of time spenton coupling the sub-systems to the vehicle. Components and accessoriesof the power electronics, such as electrical cables, wires, etc., may beattached to the cradle instead of the vehicle frame, reducing alikelihood of entanglement and/or detachment. The cradle may be mountedto the vehicle frame with rubber supports to inhibit transmission ofvibrations from the sub-systems to the vehicle frame, therebysuppressing transfer of vibrational energy at a single contact point,rather than at multiple connection points when the sub-systems areindividually coupled to the vehicle frame. As a result, electrificationof the heavy-duty vehicle is enabled at low cost and high efficiencywith rapid assembly time.

The disclosure also provides support for an electric vehicle,comprising: a battery pack for supplying current to an electric motor ofthe electric vehicle, the battery pack arranged in a chassis of theelectric vehicle and configured to form part of a floor of the electricvehicle, a motor arranged adjacent to the chassis and coupled to frontwheels of the electric vehicle, the front wheels having hub assemblieshousing drive shaft adapters, wherein the drive shaft adapters areconfigured to permanently couple the hub assemblies to drive shafts ofthe front wheels, and a cradle positioned adjacent to the chassis alonga frame of the electric vehicle, the cradle configured to be mountedwith electrical sub-systems of the electric vehicle. In a first exampleof the system, the battery pack is embedded in the chassis and a coverof the battery pack forms a portion of a surface of the chassis andwherein the chassis forms the floor of the electric vehicle. In a secondexample of the system, optionally including the first example, thebattery pack is removably arranged in the chassis of the electricvehicle and the chassis is a skateboard chassis with a low verticalpositioning in the electric vehicle. In a third example of the system,optionally including the first and second examples, the battery pack hasa sub-structure independent of the chassis and includes at least one ofa slave-master battery management system, connectors resistant tomultiple spark discharge, pre-charge capability, and integrated heatpads. In a fourth example of the system, optionally including the firstthrough third examples, the chassis extends from behind the front wheelsto a rear end of the electric vehicle and wherein the battery pack isarranged in the chassis in a region between the front wheels and rearwheels of the electric vehicle. In a fifth example of the system,optionally including the first through fourth examples, the drive shaftadapters extend through a central opening of each of the hub assembliesand do not rotate relative to the hub assemblies. In a sixth example ofthe system, optionally including the first through fifth examples, thedrive shaft adapters are configured to receive ends of the drive shaftsin an inner passage of each of the drive shaft adapters. In a seventhexample of the system, optionally including the first through sixthexamples, the drive shaft adapters circumferentially surround the endsof the drive shafts and form a constant-velocity joint with the driveshafts. In an eighth example of the system, optionally including thefirst through seventh examples, the cradle is attached to the frame ofthe electric vehicle with a rubber support arranged in between, therubber support configured to suppress transmission of vibrations. In aninth example of the system, optionally including the first througheighth examples, the cradle has one or more compartments configured tohouse the electrical sub-systems and wherein the electrical sub-systemsare directly coupled to a structure of the cradle and not the frame ofthe electric vehicle.

The disclosure also provides support for an electrical system of aheavy-duty vehicle, comprising: a battery pack embedded in a chassis ofthe vehicle, the chassis forming a floor of the vehicle, and a pluralityof sub-system power electronics electrically coupled to the battery packand mounted to a cradle. In a first example of the system, the cradle ispositioned along a common horizontal plane as the chassis and arrangedin a region along an underside of the vehicle between a front edge ofthe chassis and a front end of the vehicle. In a second example of thesystem, optionally including the first example, the cradle has a frameformed of a rigid, durable material and wherein the plurality ofsub-system power electronics is directly attached to the frame of thecradle. In a third example of the system, optionally including the firstand second examples, the frame of the cradle includes a firstcompartment stacked vertically over a second compartment and each of thefirst compartment and the second compartment are configured to encloseone or more of the plurality of sub-system power electronics. In afourth example of the system, optionally including the first throughthird examples, one or more of the plurality of sub-system powerelectronics are coupled to external surfaces of the frame of the cradle.In a fifth example of the system, optionally including the first throughfourth examples, the plurality of sub-system power electronics includesone or more of an inverter, a battery charger, a controller, a pump, anair conditioning compressor, a junction box, and a fuse.

The disclosure also provides support for an electric vehicle,comprising: a battery pack embedded in a chassis of the vehicle, thechassis forming a floor of the vehicle, and a motor arranged in front ofthe chassis and between front wheels of the vehicle, the motor drivingrotation of the front wheels, wherein the front wheels have wheel hubassemblies housing drive shaft adapters configured to couple to driveshafts of the front wheels. In a first example of the system, the driveshaft adapters are arranged between ends of the drive shafts and thewheel hub assemblies, within central openings of the wheel hubassemblies, and wherein the wheel hub assemblies are four-wheel drivewheel hub assemblies. In a second example of the system, optionallyincluding the first example, the drive shaft adapters have a firstportion with a first inner diameter contiguous with a second portionwith a second, larger inner diameter and wherein the first portion isconfigured to receive the ends of the drive shafts and the secondportion is configured to interface with a wheel cover and a wheelbearing of the wheel hub assemblies. In a third example of the system,optionally including the first and second examples, the wheel hubassemblies with the drive shaft adapters are configured to be compatiblewith regenerative braking.

In another representation, an electric vehicle includes a battery packembedded into a chassis of the vehicle, the battery pack forming aportion of a floor of the vehicle. In a first example of the electricvehicle, the battery pack is arranged in a recess of the chassis andforms a continuous unit with the chassis. A second example of theelectric vehicle optionally includes the first example, and furtherincludes, wherein the chassis forms the floor of the vehicle and extendsfrom behind front wheels of the vehicle to a rear end of the vehicle andwherein a length and a width of the battery pack is less than a lengthand a width of the chassis. A third example of the electric vehicleoptionally includes one or more of the first and second examples, andfurther includes, wherein the battery pack is biased towards a lowerportion of the chassis and a removable cover of the battery forms aportion of a bottom surface of the chassis. A fourth example of theelectric vehicle optionally includes one or more of the first throughthird examples, and further includes, wherein the removable coverincludes reinforcing rails and braces extending between the rails andside edges of the removable cover. A fifth example of the electricvehicle optionally includes one or more of the first through fourthexamples, and further includes, wherein the battery pack is configuredto be removable from the chassis. A sixth example of the electricvehicle optionally includes one or more of the first through fifthexamples, and further includes, wherein the removable cover has aplurality of apertures for receiving fasteners.

In another representation, an electric vehicle includes a drive shaftadapter positioned between a front drive shaft and a front wheel hubassembly of the vehicle, the drive shaft adapter configured topermanently couple to the front drive shaft. In a first example of theelectric vehicle, the drive shaft adapter has a tubular structure withan inner passage aligned with a central axis of rotation of the frontwheel hub assembly. A second example of the electric vehicle optionallyincludes the first example, and further includes, wherein the driveshaft adapter has a first portion contiguous with a second portion alonga length of the drive shaft adapter and wherein the first portion has asmaller inner diameter than the second portion. A third example of theelectric vehicle optionally includes one or more of the first and secondexamples, and further includes, wherein the inner diameter of the firstportion of the drive shaft adapter is similar to an outer diameter ofthe front drive shaft and the first portion of the drive shaft adapteris configured circumferentially surround an end of the drive shaftadapter. A fourth example of the electric vehicle optionally includesone or more of the first through third examples, and further includes,wherein the second portion of the drive shaft adapter has a flange withfastener openings and wherein the flange is coupled to a wheel bearingof the front wheel hub assembly via a combination of a press-fitconnection and fasteners inserted through the fastener openings. A fifthexample of the electric vehicle optionally includes one or more of thefirst through fourth examples, and further includes, wherein the driveshaft adapter is in direct contact with the wheel bearing of the frontwheel hub assembly and the drive shaft adapter does not rotate relativeto the front wheel hub assembly. A sixth example of the electric vehicleoptionally includes one or more of the first through fifth examples, andfurther includes, wherein the drive shaft adapter, the drive shaft, andthe front wheel hub assembly rotate in unison.

In yet another representation, an electric vehicle includes a pluralityof sub-system power electronics mounted to a cradle, where the cradle iscoupled to a frame of the vehicle between a front end of the vehicle anda chassis of the vehicle. In a first example of the electric vehicle,the cradle has a frame formed of a rigid, durable material. A secondexample of the electric vehicle optionally includes the first example,and further includes, wherein the plurality of sub-system powerelectronics is attached to the frame of the cradle without rubbersupports in between. A third example of the electric vehicle optionallyincludes one or more of the first and second examples, and furtherincludes, wherein the plurality of sub-system power electronics areelectrically coupled to a battery pack of the vehicle via electricalcables. A fourth example of the electric vehicle optionally includes oneor more of the first through third examples, and further includes,wherein the electrical cables and other connectors of the plurality ofsub-system power electronics are coupled to the frame of the cradle andnot to the frame of the vehicle. A fifth example of the electric vehicleoptionally includes one or more of the first through fourth examples,and further includes, wherein the plurality of sub-system powerelectronics includes controllers communicatively coupled to a controlunit of the vehicle.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1. An electric vehicle, comprising: a battery pack for supplying currentto an electric motor of the electric vehicle, the battery pack arrangedin a chassis of the electric vehicle and configured to form part of afloor of the electric vehicle; a motor arranged adjacent to the chassisand coupled to front wheels of the electric vehicle, the front wheelshaving hub assemblies housing drive shaft adapters, wherein the driveshaft adapters are configured to permanently couple the hub assembliesto drive shafts of the front wheels; and a cradle positioned adjacent tothe chassis along a frame of the electric vehicle, the cradle configuredto be mounted with electrical sub-systems of the electric vehicle. 2.The electric vehicle of claim 1, wherein the battery pack is embedded inthe chassis and a cover of the battery pack forms a portion of a surfaceof the chassis and wherein the chassis forms the floor of the electricvehicle.
 3. The electric vehicle of claim 1, wherein the battery pack isremovably arranged in the chassis of the electric vehicle and thechassis is a skateboard chassis with a low vertical positioning in theelectric vehicle.
 4. The electric vehicle of claim 1, wherein thebattery pack has a sub-structure independent of the chassis and includesat least one of a slave-master battery management system, connectorsresistant to multiple spark discharge, pre-charge capability, andintegrated heat pads.
 5. The electric vehicle of claim 1, wherein thechassis extends from behind the front wheels to a rear end of theelectric vehicle and wherein the battery pack is arranged in the chassisin a region between the front wheels and rear wheels of the electricvehicle.
 6. The electric vehicle of claim 1, wherein the drive shaftadapters extend through a central opening of each of the hub assembliesand do not rotate relative to the hub assemblies.
 7. The electricvehicle of claim 1, wherein the drive shaft adapters are configured toreceive ends of the drive shafts in an inner passage of each of thedrive shaft adapters.
 8. The electric vehicle of claim 7, wherein thedrive shaft adapters circumferentially surround the ends of the driveshafts and form a constant-velocity joint with the drive shafts.
 9. Theelectric vehicle of claim 1, wherein the cradle is attached to the frameof the electric vehicle with a rubber support arranged in between, therubber support configured to suppress transmission of vibrations. 10.The electric vehicle of claim 9, wherein the cradle has one or morecompartments configured to house the electrical sub-systems and whereinthe electrical sub-systems are directly coupled to a structure of thecradle and not the frame of the electric vehicle.
 11. An electricalsystem of a heavy-duty vehicle, comprising: a battery pack embedded in achassis of the vehicle, the chassis forming a floor of the vehicle; anda plurality of sub-system power electronics electrically coupled to thebattery pack and mounted to a cradle.
 12. The electrical system of claim11, wherein the cradle is positioned along a common horizontal plane asthe chassis and arranged in a region along an underside of the vehiclebetween a front edge of the chassis and a front end of the vehicle. 13.The electrical system of claim 11, wherein the cradle has a frame formedof a rigid, durable material and wherein the plurality of sub-systempower electronics is directly attached to the frame of the cradle. 14.The electrical system of claim 13, wherein the frame of the cradleincludes a first compartment stacked vertically over a secondcompartment and each of the first compartment and the second compartmentare configured to enclose one or more of the plurality of sub-systempower electronics.
 15. The electrical system of claim 13, wherein one ormore of the plurality of sub-system power electronics are coupled toexternal surfaces of the frame of the cradle.
 16. The electrical systemof claim 11, wherein the plurality of sub-system power electronicsincludes one or more of an inverter, a battery charger, a controller, apump, an air conditioning compressor, a junction box, and a fuse.
 17. Anelectric vehicle, comprising: a battery pack embedded in a chassis ofthe vehicle, the chassis forming a floor of the vehicle; and a motorarranged in front of the chassis and between front wheels of thevehicle, the motor driving rotation of the front wheels, wherein thefront wheels have wheel hub assemblies housing drive shaft adaptersconfigured to couple to drive shafts of the front wheels.
 18. Theelectric vehicle of claim 17, wherein the drive shaft adapters arearranged between ends of the drive shafts and the wheel hub assemblies,within central openings of the wheel hub assemblies, and wherein thewheel hub assemblies are four-wheel drive wheel hub assemblies.
 19. Theelectric vehicle of claim 18, wherein the drive shaft adapters have afirst portion with a first inner diameter contiguous with a secondportion with a second, larger inner diameter and wherein the firstportion is configured to receive the ends of the drive shafts and thesecond portion is configured to interface with a wheel cover and a wheelbearing of the wheel hub assemblies.
 20. The electric vehicle of claim17, wherein the wheel hub assemblies with the drive shaft adapters areconfigured to be compatible with regenerative braking.